Field of the Invention
The disclosure relates generally to equipment used with liner and retainers in cylindrical cavities. More specifically, the disclosure relates to a cylindrical liner retainer, such as for pumps.
Description of the Related Art
The efficiency of maintenance on equipment such as oilfield equipment can have a dramatic impact on profitability. A faster repair and restart of operation can be valuable. One area of need is to change quickly a cylindrical liner retainer assembly in equipment that repeatedly wears out such liners.
FIG. 1 is a schematic perspective view of an exemplary known pump assembly having power end and fluid end. FIG. 2 is a schematic cross sectional view of the known pump assembly of FIG. 1. FIG. 3 is a schematic cross sectional perspective view of the known fluid end of FIG. 2 with a replaceable cylinder liner and associated components to retain in position. FIG. 4 is a schematic assembly view of the cylinder liner with the liner bushing and liner nut shown in FIG. 3. The pump assembly 2 generally includes a power end 4 coupled with a fluid end 6. The power end 4 can include an engine, motor, or other prime mover. The fluid end can include inlets, outlets, valves, and flow paths. A piston rod assembly 8 couples the power end 4 with the fluid end 6 and reciprocates within a cylinder liner 12 held in position by a liner bushing 14 and coupled to a fluid end portion 16 with a liner nut 22. The piston reciprocation within the cylinder liner alternatively pulls fluid into the pump end 6 from an inlet 18 and then pushes the fluid through the pump end out of the outlet 20.
The life of a typical chrome iron liner in an oil field pump can be 1000 hours or less. To install a replacement cylinder liner at normal operating pressures and size of an oil field pump, a service person usually needs to exert 4000 foot-pounds of torque on the liner nut 22. This large amount of torque is equivalent to a 150 pound service person hanging with the person's full weight onto a 27 foot long pipe attached to the liner nut to create the torque. Typically, rods or pipes and large hammers are used to turn the liner nut 22 to the required torque, inviting accidents and injuries. The reverse procedure can be applied to remove the liner nut. After the liner nut is removed, the cylinder liner is removed often with an adaptor to connect to the piston positioned within the cylinder liner and an external groove on the cylinder liner. Then, the piston is retracted away from the fluid end toward the power end to remove the liner with the piston. After replacement of the cylinder liner, the liner nut again needs to be torqued to 4000 foot-pounds in such applications. Other applications may vary in the torque requirements.
There remains a need for an improved cylinder liner assembly that can be used to install and remove the cylinder liner. The present invention offers such a solution.